The present invention relates generally to the field of engraving, stamping and/or marking a workpiece with numerical, alphabetical and/or other visual intelligence. More particularly, the present invention relates to a die holder for moving a die having raised characters into and out of operative engagement with a workpiece to be marked by the die.
Although die holders of various types are well known in the art, they have in large measure varing drawbacks and disadvantages. One such drawback associated with conventional die holders is that upon application of an excessive torque to the spindle which supports the die (during the workpiece-marking operation), tending to rotate the spindle by an amount in excess of that which the spindle and/or its associated parts in the die holder have been designed for, there is the likelihood that the spindle and/or its associated parts may be overloaded and damaged, e.g. fractured or bent beyond repair.
A second such drawback involves the manner by which the die holder and die are withdrawn from a workpiece after the latter has been marked by the die. Since conventional die holders employ return-springs or the like for turning the spindle to its at-rest position immediately when the die is withdrawn and released slightly from the workpiece, before the die holder can be safely withdrawn from the workpiece by an amount which prevents the raised characters of the die from rotatably colliding with and scoring the workpiece as the spindle and the die are together turned to their common at-rest position, such return-springs rotate the spindle and die too early causing the raised characters of the die to bruise the workpiece.
One conventional means of preventing the aforementioned mishap from occuring is the use of a pawl-and-ratchet assembly which, until activated to release the spindle for rotation to its at-rest position when the die holder and die are withdrawn sufficiently from the workpiece, holds the spindle and die in a given rotary position during the period in which the die holder and die are initially withdrawn from the workpiece to prevent the die from marring or otherwise damaging the workpiece. However, the use of a pawl-and-ratchet assembly is unduly complicated and expensive.